Missing Guns in RE: UC

I've been playing through Resident Evil: Umbrella Chronicles with my brother, and we've beat the main storyline and a good bit of the side missions. Let me just say that the final boss is much easier with two people.
We seem to be missing one grenade launcher, one magnum, and one rocket launcher, the bottom ones of each.
Does anyone know what I have to do to unlock them?

The Magnum is in HUNK's mission. You'll end up in the area with the big statue in the middle. Shoot the double doors to the left of it or throw a grenade. When you can enter, It's pretty much in front of you along with a lot of Zombies. You get one of the launchers in Dark Legacy 2, if I remember correctly.

I got them all. If you come to an area that looks like it has stuff you can destroy, rather than shooting around, just chuck a grenade. Make sure it's your 2nd trip through so you know ahead of time to throw the grenade.

Well, I haven't been able to unlock Hunk's mission or Dark Legacy 2 just yet, so I was kinda hopeful that they'd be in one of those missions.
I have an S rating and all the files in Train Derailment and the Wesker side missions there, and I have at least an A rating and all the files in the Mansion Incident, including an S rating on the first mission and two S ratings in Rebecca's side missions with Richard there (That snake is a bastard if all you have left is the handgun) So I don't think I'm missing anything in those chapters.
Unfortunately I don't have anything other than an occasional A rating on Raccoon's Destruction or Fall of Umbrella... you need some 40+ criticals I haven't been able to pick up yet... though between my brother and I we usually get an S rating on objects destroyed. so maybe I just need to bring in the ole' grenade launcher and let loose.
I'd love any specific info but I'll just follow the leads I have for now, thanks!

Well, I haven't been able to unlock Hunk's mission or Dark Legacy 2 just yet, so I was kinda hopeful that they'd be in one of those missions.
I have an S rating and all the files in Train Derailment and the Wesker side missions there, and I have at least an A rating and all the files in the Mansion Incident, including an S rating on the first mission and two S ratings in Rebecca's side missions with Richard there (That snake is a bastard if all you have left is the handgun) So I don't think I'm missing anything in those chapters.
Unfortunately I don't have anything other than an occasional A rating on Raccoon's Destruction or Fall of Umbrella... you need some 40+ criticals I haven't been able to pick up yet... though between my brother and I we usually get an S rating on objects destroyed. so maybe I just need to bring in the ole' grenade launcher and let loose.
I'd love any specific info but I'll just follow the leads I have for now, thanks!

yeah, the best way to get all the files is whenever you come into a room w/ a ton of crap on the walls, just throw a grenade and 1 or 2 will pop up.

the grenade launcher is like on the third mission of the first chapter maybe the fourth i forget, but its the one when you go down the elevator. Before you go down the elevator there is some stuff to break to find the grenade launcher. sorry if i was vague